Apparatus for insulating electrical conductors



Oct. 16, 1945. -R 2,387,191

APPARATUS FOR INSULATING ELECTRICAL CONDUCTORS Filed Oct. 19, 1943 2 Sheets-Sheet l INVENTOR C. N. 3 T0 VER A TTORNE Y Patented Oct. 16', 1 945 APPARATUS FOR INSULATING ELECTRICAL commc'rons Clyde N. Stover, Towson, Md., assignor to western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application October 19, 1943, Serial No. socLsss l Claims. (Cl. 66-9) This invention relates to methods or and apparatus for insulating electrical conductors and more particularly to methods or and apparatus for simultaneously applying a textile insulation upon a conductor and impregnating the insulation with a weatherprooflng and insulating compound.

In the insulation of wire conductors with textile material, one method has consisted of knitting a covering; of unimpregnated textile'materlal upon the conductor, alter which the insulating and weatherprooflng material is applied to the unimpregnated material. It is diiilcult to imp egnate material already positioned on the conductor, and as a result,'the interstices in and between the individual strands of the material often are not thoroughly impregnated with the weatherprooflng and insulating material. This method is also disadvantageous because 01 the separate equipment, time and labor necessary to perform the two operationsseparately. .An alternate method has consisted of applying the 'a pipe 22: which connects the head l0 and the so chamber 2|. The impregnating material may weatherprooflng and insulating material to the strands before they are placed on the conductor, but in the use of this method the strands are sticw and difllcult to handle and extra time, equipment and labor are required to treat the strands.

It is an object of this invention to provide new and improved methods of and apparatus ior insulating electrical conductors.

In one embodiment of this invention, a conductor to be covered with an insulating and weatherprooflng Jacket is passed through a knitting head which knits the strands tobe applied to the conductor in the form-oi a co'ne shaped ted strands-tightened on the conductor. An insulating. and weatherprooflng compound is strands forming the open portion of the coneshaped textile basket. This compound thoroughly covers the knitted strands so that when they" are drawn tightly around the conductor by the Fig. '2 is an enlarged," fragmentary. vertical sectional view oi the apparatus shown in Fig. 1, and

Fig. 3 is an enlarged, fragmentary, vertical sectional view of an alternative form of apps: ratus embodying the invention. 1

Referring now to the drawings, an extruding head I0 is composed 01. an inner core tube ll surrounded by an outer cylinder l3. The core tube I i has formed therein a passage l2 through which a conductor I! to be insulated and weatherprooied is advanced downwardly from a suitable source of supply (not shown). The outer cylinder I3 is concentric with the inner tube II and the two form an annular extrusion chamber v 19 into which a viscous impregnating material 20 I having insulating and weatherprooilng qualities may be forced from a supply chamber 2i through be ester gum, asphalt, rubber cement, paint, or

any other well known type of waterproofing, in-

sulating orweather resisting material. Nitrogen or other suitable gasunderhigh pressure is supplied to the chamber from any suitable source through a valve 28 in the top or the chamber to basket. the apex oi which is formed by theknitforce the impregnating material through the chamber it. A resistance wire 2t of Nichrome or other suitable material coiled around the chamber 2|, the pipe 22, and the cylinder I! are connected in accnventional manner to a source 01 current 25 for heating the viscous material 20 to a temperature at which the material will flow freely through the apparatus. By using nitrogen gas as the medium to apply pressure to the hot material 2!), oxidation of. the material is avoided. An inwardly positioned, inner surface 26 of the outer cylinder I I and an'outwardly curved sura lace 28 formed upon the exterior of the core forced upon and between the loosely knitted 4 tube N r 'fl-nnular ion P e 29 hitting head, the insulating and weatherprooflng material completely fills all the spaces in. and between the strands and thoroughly impregnat'es them.

A complete understanding oi the. invention may be obtained from the following detailed description taken in connection with theappended drawings, in which: e

Fig. 1 is a side elevation of an apparatus embodyin the invention by means or which meth which is threaded into the upper end of the cylinder II. The adjusting screw 30 may be screwed fartherinto or out of the cylinder I3, to enlarge, diminish or close oil completely the extrusion passage 28, as desired. A set screw. 3| secures the plug in any adjusted position.

A plurality or knitting needles 33 or conventional design are positioned on a knitting head having a bore 25 therethrough, which expands into an enlarged conical opening 38 near the upper end. thereof. The conlcal opening l8 ods embodying the inventlon'maybe practiced; 5 forms with conical ends I! and 39 on the lower respect to the ends of the core tube II and cylinder "l3, respectively, an annular, conical passage 40 therebetween. In the normal operation or the knitting head, the needles 33-32 form a plurality of strands 42-42 into an open. knitted cone-shaped basket 43 and the several parts of the apparatus are 50 related that the basket 43 is formed within the annular, conical passage 40. As the conductor l and the knitted covering enter the bore 35, the covering is drawn tightly upon the conductor to form a closely fitting covering 45 there- In the operation or this form of the invention, the conductor I5 is drawn from a suitable supply through the passages I2 and II by a capstan 41. The strands 42-42 are first knitted by the knitting head 34 into the open, cone-shaped basket 43 and are then drawn tightly around the conapparatus, the needles lit-I33 term a plurality of strands 142-442 into an open, knitted coneshaped basket I43 which slides along irustoconb cal surfaces It! and I3! formed on the inside or the lower ends of the core III and the cylinder II), respectively, as the knitted basket is drawn upon the moving conductor H5. The conductor I II is drawn by the capstan (not shown) through the bore its and passage H2 and the knitted basket I43 is drawn into a close-fitting covering I45 about the conductor II! in the passage 2.

'As the basket I43 is drawn closely around the ductor I5 to term a knitted covering 65 thereon.

As the open knitted basket 43 is being formed, the

impregnating material is forced into the inte- I rior of the basket through the extrusion passage 29, thoroughly covering the strands 42-42 thereof and filling the interstices between the individual knitted strands. As the cone-shaped basket 43 is drawn tightly around the conductor IS, the impregnating material 20 is forced into and around the individual knitted strands 42-42 by the pressure of the strands themselves and by the pressure of the conical opening 40, and the knitted covering 45 formed on the conductor I5 is thoroughly saturated and coated with the impregnating material 20. The impregnating material is cooled and hardened on the conductor II as the conductor passes from the capstan 41 to a suitable takeup reel (not shown).

Fig. 3 of the drawings illustrates an alternative method of and apparatus for apply Ag an impregnating material to a knitted covering on a conductor as the covering is being formed. In this embodiment of the invention, an extruding head IIIl consists of an inner core tube III surrounded by an outer cylinder II8. The core tube II has formed therein a passage H2 through which a conductor III to be insulated and weatherproofed is drawn upwardly through the apparatus by a capstan (not shown) similar to the capstan 41 shown in Fig. 1 of the drawings. The outer cylinder I I3 is concentric with the core tube III and forms therewith an annular extrusion chamber us into which a viscous imprega nating material I20 heated by a resistance wire I24 and having insulating and weatherprooilng qualities is forced in a similar manner and rrom apparatus similar to that hereinabove described and illustrated in Fig. 1 or the drawings.

moving conductor I II, the impregnating material I20 is ontinuously extruded through the passage I20 into and around the loosely knitted basket I43, and the resultant knitted covering I48 formed on the conductor H5 is thoroughly saturated and coated with the impregnating material -I20. The surface I88 acts as a die to force the impregnating material into the knitted covering and insures thorough impregnation thereof. The impregnating material is cooled and hardened on the conductor 8 as the conductor passes to a suitable takeup re'el (not shown).

As will be readily seen, the textile material and the interstices between the individual strands thereof will be thoroughly impregnated and filled with the insulating and weatherproofing material by use of the above described methods and appsratus and the material may be applied to either the outer or the inner part of the knitted sheath,

. whichever is desired. This apparatus is simple in A curved annular surface I26 formed upon the V exterior of the flared end of the core tube II I and a complementary curved annular surface I28 formed upon the interior of the cylinder II! together form an annular extrusion passage I2Il through which the material I24 may be forced in the form of a thin, annular stream. The core tube III is secured to an adjusting screw (notshown) similar to the hereinabove described screw 30 and may be adjusted longitudinally with cylinder H3 to open or close the passage I29 in a manner similar to that disclosed in the description or the apparatusillustrated in Figs. 1 and 2 of the drawings. A plurality of knitting needles are positioned on a knitting head I14, which is also of conventional design and has a bore ll! therethrough concentric with the passage I I2.

' In the operation of this alternative form of the Iii-I33 or conventional design construction. yet is cifective to permit conductors to be insulated rapidly and thoroughly by simple and inexpensive processes.

What is claimed is:

1. An apparatus for insulating and weatherproonng conductors, comprising a knitting head having a conical aperture therein through which a conductor maybe advanced, the knitting head being designed to knit a plurality of strands into a cone-shaped textile basket about a conductor within the conical aperture and to draw the textile basket down into a tight, compact covering onthc conductor, and an extruding means in-' cluding a cylindrical core having a passage therein through which the conductor is advanced to the knitting head, and an outergcylinder enclosing the core and forming therewith an extruding passage through which an insulating and weatherprooiing material may be extruded upon the cone-shaped basket as it is formed about the conductor.

2. An apparatus for insulating and weatherprooiing conductors comprising a knitting head having a conical aperture therein through which a conductor may be advanced, and designed to knit a plurality-of strands into a cone-shaped basket about a conductor and to draw the knitted textile into a tight covering -around theconductor advancing through the conical aperture, and an extruding means including a cylindrical core having a passage therein through which the conductor is advanced to the knitting head and an outer cylinder enclosing'the core and concentric therewith to form an extruding passage transverse to the cone-shaped basket through which to ext-rude an insulating and weatherprooflng material upon the cone-shaped basket as it is formed about the conductor and just before'the basket is drawn down'on the conductor into a compact covering.

3. An apparatus for insulating and weather-. proofing conductors comprising a knitting head having a conical aperture therein through which a conductor-may be advanced to knit a plurality of strands into a cone-shaped basket which is complementary to the conical aperture and is to be drawn on the conductor being advanced through the conical'aperture, and an extruding means including a cylindrical core having a passage therein through which the conductor is advanced to the knitting head and an outer cylinder enclosing the core and forming therewith an annular extruding passage through which an insulating and weatherprooflng material is extruded upon the inside of the basket as it is drawn on the conductor.

4. An apparatus for insulating and weatherproofing conductors comprising a knitting head having a conical aperture therein through which a conductor may be advanced to knit a plurality of strands into a cone-shaped basket which is drawn tightly about the conductor being advanced through the conical aperture, and an extruding means including a cylindrical core having a passage therein through which the conductor is advanced to the knitting head and an .outer cylinder enclosing the core and forming therewith an annular extruding passage to extrude an insulating and weatherprooflng material upon the outside of the basket as it is drawn pregnating material through the extrusion passage, whereby an annular stream of impregnatwhich the conductor is advanced, an outer cylinder enclosing the core tube and forming therewith an annular extrusion passage spaced from and concentric with a conductor drawn thro gh the core tube, means for forcing a plastic iming material is extruded upon the covering beq fore the covering is drawn tightly upon the article, and means for adjusting the size of the extrusion passage.

6. In an apparatus for applying protective coverings to conductors, means for forming textile strands into a covering in the form of a coneshaped basket around a conductor, means foradvancing a conductor through the formin means to draw a covering formed by the forming means closely upon the conductor, and an extruding means positioned between the forming means and the advancing means, said extruding means including a core tube, an outer cylinder positioned around the core tube and cooperating therewith to form an annular passage directed substantially perpendicularly to the cone-shaped portion oi the covering for directing a liquifled impregnating material substantially perpendicularly against that portion of the covering, and means for adjusting the position of the core tube relative to the cylinder to vary the size 0! said passa e. 7. In an apparatus for applying protective coverings to conductors, means for forming strands into a covering in the form of a cone-shaped basket around a conductor, means for advancing a conductor through the forming means to draw closely upon the conductor a covering formed by the forming means, a tubular extruding means provided with an annular extruding passage concentric with and spaced from the conductor to direct an annular sheet of impregnating material upon the more open portions of the coneshaped basket, and means for forcing a liquifled impregnating material through the extruding means.

CLYDE N, STOVE. 

